Seal with pyramid shaped formation

ABSTRACT

A seal assembly having a seal bumper wall with a series of pyramid shaped formations lying on the bumper wall. The formations cause their apex portion to wear down rapidly in use, while the remainder of the pyramids remain and act as slingers and/or produce a convection effect to reduce temperature along the sealed area. In another embodiment, there are two each pyramid shaped formations located on each of several thrust bumpers, which are held in position by a retainer.

BACKGROUND OF THE INVENTION

The present invention relates generally to unitized seals, and moreparticularly, to a seal having plural pyramid shaped formations designedto reduce the temperature at the bumper wall-sleeve interface and alsoto provide additional beneficial effects. The seal design provides aslinging effect to grease on the inner side of the seal and provides aslinging effect on the external contaminants on the outer side.Moreover, the seal design provides a cooling effect to the interfacebetween the bumper wall and the radial flange of the wear sleeve byutilizing the remains of the pyramid wall to create additional airconvection.

The present invention provides a sacrificial member in the bumper wallthat will abrade quickly under dynamic conditions, and thus relieve thecompressive forces acting on the bumper wall. The net effect after ashort break-in period is a line-to-line condition, between the sleeveand the remaining bumper wall, creating a barrier to environmentalcontacts. The present invention provides a tiny area, which graduallybecomes bigger, and eventually is abraded into a parallel condition withthe bumper wall on the radial flange of a unitized seal. This allows thepyramid shaped formation to wear away with a different degree ofabrasion until, when it is completely or almost completely worn away,there is substantially line-to-line contact, or an area of minimalcontact, between the bumper wall which was formed on the radial flangeof the seal member and the wear sleeve. Accordingly, the seal can beassembled and placed in use with a maximum of confidence that thepyramid formations will wear away with a small amount of scrap rubberbeing thus generated.

The present invention relates mostly to large, heavy duty unitized sealswherein the wear sleeve is normally held against rotation and fixed overan axle stub or the like by means of a rubber inside diameter (I.D.)creating an interference fit. Of course, it could have otherapplications. In one embodiment, the seal is unitized by turning up anend portion of its axial flange, and the other or radial flange is actedupon by the pyramid shaped formation. The radial flange of the wearsleeve may also engage one or more dirt or dust lips or the like toprevent undue contamination of the seal area.

The seal itself, wherein the seal is bonded to a radial flange, includesthe customary air side and oil side surfaces which meet along a sealband or line of intended contact with the wear sleeve. The seal bodyconventionally includes a groove for a garter spring and an accompanyinggarter spring to maintain the radial load on the seal. The axial endportion of the seal casing is also fitted with a rubber sleeve to allowfor the seal to be installed with a rubber O.D. (outside diameter). Theplace where the seal casing axial flange turns into the radial flangecontains a plurality of spaced apart chaplets, which arecircumferentially discontinuous, and which present a radial face whichis spaced just apart from the radial flange of the seal casing. Theseare termed “chaplets” or the like, and they terminate at a bumper wallwhich extends circumferentially around the seal casing. There are aplurality of small, spaced apart pyramid shaped formations which presentfour sidewalls, two of which have an identical shape and terminate onthe casing, and the other two of which terminate on the end faces of thechaplets.

Accordingly, it is an object of the present invention to provide an oilseal of the unitized type or other seal having a bumper wall extendingcircumferentially around its radial flange with a plurality of pyramidshaped formations spaced circumferentially apart on the bumper wall.

Another object of the invention is to provide a unitized or other styleof seal having a casing with a plurality of chaplets on its outsidediameter, with the plural pyramid shaped formations intersecting thechaplets.

Another object is to provide a plurality of pyramid shaped formationswhich are circumferentially spaced apart and in which the pyramid formsan initial contact with the sleeve, and wear an ultimately near zeroclearance with a radial flange of the wear sleeve.

Another object of the invention is to provide a pyramid shaped formationriding on a bumper wall, with an excluder or secondary seal beingprovided to increase the security of the slidable connection between theflange of the wear sleeve and the casing of the seal unit.

SUMMARY OF THE INVENTION

These and other objects and advantages of the invention are achieved inpractice by providing a seal bumper wall for a unitized seal assemblywherein the seal assembly includes a seal casing and preferably a wearsleeve, and wherein the seal casing includes a plurality ofcircumferentially spaced apart pyramid shaped formations extendingtoward and joining the wear sleeve flange, with such sacrificial pyramidshaped formations lying atop a bumper wall, and being designed withangularly related planar surfaces to wear rapidly and thereafterestablish and maintain contact with a wear sleeve, or the like, andgradually wearing down to become substantially co-planar with the bumperwall.

The manner in which these and other objects and advantages of theinvention are carried into practice will become more apparent whenconsideration is given to the following detailed description of thepreferred embodiment of the invention in which like reference numeralsindicate corresponding parts throughout.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical sectional view of a prior art type seal, showingthe seal component and the wear sleeve;

FIG. 2 is an exploded perspective view of the seal of the invention,showing the wear sleeve separated from the seal and showing the pyramidshaped formations on the bumper wall;

FIG. 2A is a greatly enlarged view showing the bumper wall, the chapletsand the pyramid shaped formation of the invention;

FIG. 3 is an enlarged vertical sectional view of the seal assembly ofthe invention;

FIGS. 4-6 show portions of the pyramid shaped formation and the bumperwall, showing the formation when new (FIG. 4); when partially worn (FIG.5); and when fully worn, and flush with the bumper wall (FIG. 6);

FIG. 7 shows an alternate embodiment of the invention, with the bumperseach having two pyramids.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

The present invention is capable of use with large, heavy duty seals. Itis useful with seals that are not large nor heavy duty. Although usedprimarily with unitized seals, the use is not so limited. Where anadditional component, such as a plastic spacer is used between the sealand the sleeve, this concept could be applied.

Referring now to the drawings in greater detail, there is shown a priorart unitized seal generally designated 10, including a stationary wearsleeve generally designated 12 with a rubber I.D. 14 and a major axialflange 16 with a curled inward tip 18 which serves to unitize the seal10. This wear sleeve 12 includes a radially extending flange 20.

The other component of the unitized seal 10 is a rotary portiongenerally designated 22 and shown to include a radial flange 24, astepped axial flange 26, with a rubber O.D. (outside diameter) 28. Thisknown type of seal generally designated 10 includes a portion 32 forattachment to the seal body 34.

The seal body 34 conventionally includes an air and oil side surfaces36, 38 meeting along a seal band 40 which engages the axial flange 16 ofthe wear sleeve to create the primary seal.

The seal body 34 also conventionally includes a garter spring 42contained within a spring groove 44. The seal may have an auxiliary dirtlip 46 or an excluder lip 48, or have neither or have both. The radiallyouter portion of the radial flange 24 contains a circumferentiallyextending rib 50 which is attached in part to one of a plurality ofchaplets 52. The foregoing is merely typical of a prior artconstruction.

Referring now to the present invention, and particularly to FIG. 3,there is shown a unitized seal generally designated 110, a stationarywear sleeve 112 with a rubber inside diameter 114. This seal has aconventionally existing major axial flange 116, with a curled tip 118creating a unitized seal. A radially extending wear sleeve flange 120,about which more will be said later, finishes this component 112.

The other major component of the unitized seal 110 is a rotary portiongenerally designated 122, and this includes a radially extending flange124, a stepped axial flange 126, and a rubber outside diameter (O.D.)128. This seal generally designated 110 also includes a portion 132 thatis attached to a seal body 134. The seal body 134 conventionallyincludes air and oil side surfaces 136, 138, meeting along a seal band140.

The seal body 134 may include a garter spring 142 disposed in a springgroove 144. The seal may have an auxiliary or dirt lip 146, or anexcluded lip 148, and may include one or both of these lips 146, 148,neither being essential to the practice of the invention. Toward theradially outer portion of the radial flange 124 is a circumferentiallyextending bumper wall 150 which is attached to the inner portion 151 ofone of the chaplets 152.

In addition, a feature which is novel is the pyramid shaped formation(FIG. 2A) generally designated 156, and this includes a large angledface 158 which extends down and joins the flange 124, it also includesan oppositely directed angled face 160 which Fig. also extendsdownwardly toward the flange 124. There is an included angle of about90° between the two faces 158, 160. The pyramid also has two smallerfaces 162, 164 with an included angle between them of about 90° andwhich terminate on the face 15 of a chaplet 152. The pyramid shapedformation includes a sharp point 166 at its apex.

The seal is installed as an ordinary seal, except that the apex 166 ispressed into contact with the radial flange 120. Upon initial rotationof the parts 110, 112, with respect to each other, the pyramidimmediately begins to wear away. This abrasion relatively rapidly wearsaway the apex portion 166 of the pyramid 156, which relieves thecompressive force acting on the bumper wall 150. As a result, there is amore or less line-to-line condition between the remaining wall 150 andthe wear sleeve radial flange 120. The excluder lip 148 can readilyaccommodate this movement since it flexes relatively freely with theonset of an axial force. As soon as the apex and the top of the pyramidis worn away, there is an immediate reduction of temperature at thebumper wall/wear sleeve interface.

The pyramid provides a slinging effect to grease which is on eitherside, and the slinging effect extends to external contaminants on itsouter side.

In addition to the foregoing, there is also a cooling effect betweenpyramid and the wear sleeve which utilizes the walls of the pyramid tocreate additional air convection. As a result of the foregoing, there isa reduction in possible false claims of leakage which arise due togrease purging during installation. The slinging effect of the outerpyramid walls on the environment aid in excluding the contaminants.

In contrast to current bumper geometry, there is a large surface areawhich allows for a generation of an excessive frictional heat underdynamic conditions. The flat surface of the bumper wall and the straightwall of the radial flange do not allow for effective disposition of theaxial installation load in the prior art. Thus, there is an entire topsurface of the wall that is subject to being abraided. This can alsoproduce small particles that may act as contaminants in the operation ofthe seal. However, the new bumper geometry minimizes the surface area ofcontact and allows for improved distribution of the installation load,thereby reducing frictional heat. The geometry also allows for airconvection to take place since there are now convection currents ineffect to help cool and reduce the temperature at the wear sleeve/bumperwall interface.

Referring now to another embodiment of the invention, and particularlyto FIG. 7, there is shown a unitized seal assembly generally designated210, including a rotary wear sleeve generally designated 212. The seal210 has a conventionally existing major axial flange 216, with a curledtip 218 creating a unitized seal, and a rubber inside diameter 214. Aradially extending flange 220, mounts a seal body 234.

The other major components include is a fixed portion or wear sleevegenerally designated 222, and this includes a radially extending flange224, a pressed-in axial flange 226, and a stop flange 227. This sealgenerally designated 210 also includes a radially outermost portion 232that is bonded to the seal body 234. The seal body 234 conventionallyincludes air and oil side surfaces 236, 238, meeting along a seal band240.

The seal body 234 includes an outwardly acting garter spring 242disposed in a spring groove 244. The seal has an auxiliary or dirt lip246, or an excluder lip 248, and may include one or both of these lips246, 248; however, neither is essential to the practice of theinvention.

In addition, a novel feature which is embodied in a somewhat differentform than in the earlier embodiments is the plural pyramid shapedformations (FIG. 7) generally designated 256 and 258 which extend fromthe bumper 260. The bumper 260 is one of six in this embodiment. Thebumpers 260 each are secured by a retainer or belt 262 which allows thebumpers 260 to be spaced apart, but keep the same orientation. Thepyramids are the same shape as their counterparts in FIG. 2A.

The seal is installed as an ordinary seal, except that there are twoapexes, one on each formation. Upon initial rotation of the parts 210,212, with respect to each other, the two pyramids immediately begin towear away. This abrasion relatively rapidly wears away the apex portions270 of the pyramids 256, 258, which relieves the compressive forceacting on the seal flanges. As a result, there is a more or lessline-to-line condition between the radial flanges and the spacer 260.The excluder lip 248 can readily accommodate this movement since itflexes relatively freely with the onset of an axial or radial force. Assoon as the apex 270 and the top of the pyramid are worn away, there isan immediate reduction of temperature at interface.

The wear patterns are very similar to those shown in FIGS. 4-6, exceptthat the pyramids are entirely worn away.

The present invention anticipates that the components would be made fromrubber or plastic; however, it is conceivable that certain types ofother materials may also be used.

It will thus be seen that the present invention provides a new andeffective combination of pyramid shaped formation and a bumper wall aswell as a planar wear sleeve wall having a number of advantages andcharacteristics including those pointed out and others which areinherent in the invention.

1. A seal bumper for a seal assembly having a seal casing and a wearsleeve, said seal casing including a first axial flange and a firstradial flange, and a seal body supported on said first radial flange,said seal body having air and oil side surfaces meeting along a sealband having contact with an associated wear sleeve, and a bumper wall onsaid first radial flange, said bumper wall having a portion extendingtoward and nearly meeting said first axial flange adjacent the outerdiameter thereof and, located on said bumper wall, a plurality ofpyramid shaped formations, spaced circumferentially apart, each of saidpyramid shaped formation having an apex radially aligned with saidbumper wall, and four angularly related planar sides, two adjacent sidestapering radially inwardly and each terminating on said casing radialflange, and two opposite sides of said pyramid shaped formation taperingradially outwardly and each terminating adjacent said first axialflange, whereby said apex of said pyramid shaped formation initiallycontacts said second radial flange of said wear sleeve upon installationof said unitized seal assembly, and gradually flattens with wear tobecome substantially co-planar with said bumper wall.
 2. A seal assemblyas defined in claim 1, wherein said seal assembly is a unitized sealassembly.
 3. A seal bumper assembly as defined in claim 1 which includesplural chaplets portions positioned with a radially curved portion lyingparallel to said axial flange of said casing and an end face portionlying generally parallel to said casing radial flange.
 4. A seal bumperas defined in claim 1, wherein said first axial flange includes pluralchaplets thereon.
 5. A seal bumper as defined in claim 1, wherein saidchaplets have radially extending faces, said two side of said pyramidshaped formations tapering outwardly and terminating on the face of saidchaplets.
 6. A seal bumper as defined in claim 1, wherein said pluralityof pyramid shaped formations is equal to at least four pyramid shapedformations.
 7. A seal bumper as defined in claim 1, wherein saidplurality of pyramid shaped formations is equal to at least six pyramidshaped formations.
 8. A seal bumper as defined in claim 1, wherein saidapex lies about 0.010″ to 0.040″ above said bumper wall.
 9. A sealbumper for a seal assembly having a seal casing and a wear sleeve, saidseal casing including a first axial flange and a first radial flange,and a seal body supported on said first radial flange, said seal bodyhaving air and oil side surfaces meeting along a seal band havingcontact with an associated wear sleeve, and a bumper wall on said firstradial flange, said bumper wall having a portion extending toward andnearly meeting said first axial flange adjacent the outer diameterthereof and, located on said bumper wall, at least six pyramid shapedformations, spaced circumferentially apart, each of said pyramid shapedformation having an apex radially aligned with said bumper wall, andfour angularly related planar sides, two adjacent sides taperingradially inwardly and each terminating on said casing radial flange, andtwo opposite sides of said pyramid shaped formation tapering radiallyoutwardly and each terminating adjacent on a radially extending face ofa chaplet, the axial portion of said chaplet overlying said first axialflange, whereby said apex of said pyramid shaped formation initiallycontacts said second radial flange of said wear sleeve upon installationof said unitized seal assembly, and gradually flattens with wear tobecome substantially co-planar with said bumper wall.
 10. A seal bumperas defined in claim 9, wherein said apex lies from about 0.010 to 0.040above said bumper wall.
 11. Plural thrust bumpers for a seal assemblyhaving a seal casing and a wear sleeve, said seal casing including afirst axial flange and a first radial flange, and a seal body supportedon said first radial flange, said seal body having air and oil sidesurfaces meeting along a seal band having contact with an associatedwear sleeve having radial and axial surfaces, and plural,circumferentially spaced apart thrust bumpers lying between both of saidradial flanges and acting as spacers of enlarged size, each of saidthrust bumpers having a reduced size, pyramid shaped formation lying oneach of its two opposed radially disposed sides, and each of saidpyramid shaped formations having an apex, and four angularly relatedplanar sides, two adjacent sides tapering radially inwardly and eachterminating on an associated thrust bumper, and two opposite sides ofsaid pyramid shaped formation tapering radially outwardly and eachterminating on an associated thrust bumper, whereby said apexes of saidpyramid shaped formations initially contact said radial flange of saidwear sleeve and said radial flange of said seal assembly, and both ofsaid formations gradually flatten with wear to become substantiallyco-planar with said thrust bumper, thereby leaving a predetermined spacebetween said two radial flanges.
 12. Thrust bumpers for a seal assemblyas defined in claim 11, said thrust bumpers being circumferentiallyspaced apart and retained in position by holding means forming acontinuous belt.
 13. Thrust bumpers for a seal assembly as defined inclaim 11, wherein said thrust bumper is made from plastic.
 14. Pluralbumpers for a seal assembly as defined in claim 11, wherein said thrustbumpers are made from Delrin brand plastic.